Spark plug



Nov 13, 1928 F. L. Fox

SPARK PLUG Filed Aue;- 12. 1922 Patented Nov. 13, 1928.

UNITED STATES FREDERICK L. FOX, OF WASHINGTON, DISTRICT 0F COLUMBIA.

SPARK PLUG.

Application led August 12, 1922. Serial No. 581,529.

This invention relates to improvement-s in spark plugs, the generalobject of the invention being to provide means for keeping the spark gapclear without removing the plug from the engine.

Another object of the invention is to so form the plug that a portion ofthe wall of the shell acts as one member of the spark gap, with meansfor keeping the major portion of this wall covered and uncovering newportions when the uncovered portion has become dirty.

A still further object of the invention is to provide means whereby thecovering member for the wall can be adjusted from 'the eX- terior of themotor, by a wrench or the like,

and without removing the plug from the motor.

The invention also permits the cover member to be adjusted to expose afresh sparking surface without stopping the motor so that it is notnecessary to go to the trouble of stopping and starting the motor to indout whether or not the difficulty lies in the plug.

This invention also consists in certain other features of constructionand in the combinatioii and .arrangement of the several parts, to behereinafter fully described, illustrated in the accompanying drawingsand specifically pointed out in the app-ended claims.

In describing my invention in detail, reference will be had to theaccompanying drawings wherein like characters denote like orcorresponding parts throughout the several views, and in which Figure 1is an elevation of a plug `constructed in accordance with thisinvention.

Figure 2 is a longitudinal sectional view withthe interior parts inelevation.

Figure 3 is a longitudinal sectional view through the entire plug.

Figure 4 is a section on line 4-4 of Figure 1.

Figure 5 is a longitudinal sectional view showing a modification.

Figure 6 is a view of a further modification, parts being shown insection.

Figure 7 is a similar view of a further modiiication.

Figure 8 is a fragmentary sectional view of still another modification.

In these views 1 indicates the shell, 2 the porcelain body, 3 the nutfor holding the body in the shell and-4 the electrode which passesthrough the porcelain body and is threaded at its upper end toreceiveythe usual nuts 5. As will be seen the ground electrode is formedby the inner wall of the lower part of the shell, the electrode 4 havingits end bent, as at 6, so that the gap is formed by this bent end and apart of the wall of the shell. In carrying out my invention I provide asleeve 7 for covering the major portion of the wall forming the groundelectrode, said l sleeve having an opening 7 therein for-exposing aportion of this wall, adjacent the bent end 6 ofthe electrode 5, so asto form the spark gap. By turning this sleeve to expose new portions ofthe wall the spark gap can be kept clear and the foreign matterdeposited on the portion previously exposed will be scraped off by theedges of the sleeve forming the walls of the opening. The parts are soarranged that the sleeve can be turned without removing the plug fromthe engine and in order to keep the electrodes in their proper relativepositions the insulated body with the electrode 4 must move with thesleeve. In the lirst form of the invention the sleeve carries the body 2and is connected therewith by having a ring-shaped part 8 pressed into agroove 9 formed in the body. The outer end of the sleeve is providedwith a wrench receiving head 10 and it is provided with an enlargedcentral part 11 forming shoulders for engaging the gaskets 12 which actto make a gas tight joint between the sleeve, the shell and the nut. Thelower end ofthe sleeve is bent over the end of the shell, as shown at13, and the opening 7 extends through the inner edge of this bent overpart so that a gage or the like can be inserted into the opening to gagethe spark gap. It will thus be seen that when the spark gap becomesfilled or partly filled with foreign matter it is simply necessary toplace a wrench or thelike on the head 10 and gives the sleeve a slightrotary movement so as to expose a new portion of the wall forming theground electrode. As the porcelain body moves with the sleeve the parts6 of the electrode 4 will remain in the same position relative`to theopening 7 at all times.A As the sleeve is turned the edge wall of theopening 7 will act to scrape the foreign matter from the wall of theshell so that the sleeve `not only acts to keep the major portions ofthe wall covered but it also acts to remove carbon and the like from theparts cause a short circuit.

Iny the modification shown in Figure 5.the enlargement 11 of the sleeveis made hollow so that this part of the sleeve can yield somewhat underthe pressure of the nut and thus facilitate the-adjustment of the sleevein the l shell when a new part of the wall is to be exposed. This ligurealso shows the-end of the sleeve as being unbentwith the openingv 7extending entirely throu h the end of the l sleeve. In other respectstiis form of the invention is similar to the first form.

Figure 6 shows the invention applied to a lug, the parts of which cannotbe separated. this form of the invention the parts are held in the shellby a flange 13 on the shell being bent over upon a ring 14 which holdsthe sleeve and body in the shell. In other respects this form of theinvention is similar to those described above.

In the form shown in Figure' the ring 14 is omitted and thesleeve 7xdoes not extend through the shell at its upper end but terminates justabove the lower shoulder of the shell. The upper end of the sleeve isprovided with tongues 15 which engage recesses 17 in the porcelain bodyso that the sleeve must turn with 'the body. The upper end of theporcelain body is provided with a metal cap 18 formed to receive awrench, this cap protecting the porcelain from injury by the Wrench.Gaskets 19-are placed between the upper end of the. sleeve and the shelland between-the shell and theporcelain body so as to prevent leakage atthese points. A gasket 19 is placed between. the ange 13 of the shelland the upper shoulder of the body.

Thus when the porcelain body is turned by fa wrench or the like thesleeve will move withv the body so as to expose a new portion -jojf the'ground electrode.

In the form shown in Figure 8 the portion .l Aof the shell forming theground electrode is beveled, as at 20, and the covering portion ofthesleeve is also beveled, as at 21, so as to engage the bevel 20. Anopening 22 is formed 1n this beveled art 21. In this case the mainelectrode has its end of hook shape so as to bring the extremity withina s u-fiicient distance of the ground electrode.

From the .foregoing it will be seen that the. spark ga can be ke t clearby a slight movement of t e sleeve, t is movement being given the sleevefrom the 'outer part ofthe plug, so that it is not necessary to removethe plug fromthe engine or even stop the engine.l

It is thought from the foregoing description that the advantages andnovel features ofhmg invention will be -readily apparent.

I esire itto be understood that I may make changes in the constructionand in the combination and arrangement of the several parts, providedthat such changes fall within the scope of the appended claims.

What I claim is 1. A spark plug having one of its spark gap membersformed by a part of the wall of the shell, and an adjustable sleevecovering the Wall, said sleeve having an opening therein for exposing apart of the wall.

2. A spark plug having one of its spark gap members formed with a broadsurface, a sleeve covering the major part of this surface and leaving aportion uncovered and means for adjusting the sleeve to expose a newpart of the surface, said means being operable from the exterior of aninternal combustion engine when said spark plug is applied thereto.

3. A spark plug of the class described comprising a shell having a partof its lower wall forming the ground electrode, an insulated body in theshell, an electrode carried thereby, and a covering member for the Wallof the shell having an opening for exposing a portion of the walladjacent the main electrode and means for moving the said member withthe insulated body to bring the openingover a new portion of the wall.

- 4. A spark plug of the class described comprising a shell having partof its wall forming the ground electrode, a sleeve in the shell havingan opening therein for exposing a part of the wall, an insulated bodycarried by the sleeve and movable therewith and a main electrode carriedby the body.

5. A spark plug of the class described comprising a shell having part ofits wall forming the ground electrode, a sleeve in the shell having anopening therein for exposing a 'part of the wall, an insulated bodycarried by the sleeve and movable therewith, a main electrode carried bythe body, said opening being so formed as to permit the introduction ofa gage for measuring the spark gap.

6. In a spark plug, power and ground electrodes spaced apart to providea spark gap, means xedly associated with one of said electrodes andpartially covering the second electrode and revoluble therein forpresenting fresh sparking surfaces between the electrodes.

7. A spark plug comprising a shell, providing a ground electrode, apower electrode in the. shell, means connected with and insulated fromthe power electrode adjustably secured in the shell for rotation and forfrictional contact with'the wall of the shell, said means having anopening arranged opposite the power electrode and the walls provided bysaid opening designed for scraping engagement with the shell when thepower electrode and said means are turned in the shell to present freshsparking gaps between the ground and power electrodes.

8. A spark plug having a shell electrode formed with a cylindrical bore,a bearing sleeve encasing a portion of the insulator 'arrying a centerelectrode, said bearing sleeve being mounted for rotatable adjustment insaid shell electrode, said center electrode being formed for sparkingcooperation with the cylindrical bore of the shell electrode, and saidsleeve cooperating With the cylindrical bore forv centering the shelland center electrode to maintain a uniform spark gap between saidelectrodes. v

9. A spar: plug having lone electrode formed with a sparking surface.adjustable means covering a portion of such surface., a second electrodecarried by said means for sparking cooperation with the first electrode,and means having a part for adjusting the first-mentioned means touncover new portions of said surface of the rst-mentioned electrode forsparking cooperation with the second electrode.

10.` A spark plug having a ground electrode formed by a portion of theWall of the shell, an adjustable covering member in frictionalengagement with said Wall, a second electrode carried by said coveringmember having sparking cooperation with the wall of said groundelectrode, and means on said covering member operable to adjust saidmember for uncovering new portions of the Wall of the shell for sparkingcooperation with said second electrode.

11. Ay spark plug having a shell electrode, an insulator mounting acentral electrode, a bearing member mounting said insulator having anadj ust-able mounting in the shell electrode, and means on said memberhaving a part for cleaning the shell electrode in the rotation of saidmember.

12. A spark plug comprising a pair of relatively rotatable electrodes,and means having a part mounting one of said electrodes and having arotatable bearing inthe other electrode and centering said electrodes,said means serving to maintain uniform sparking cooperation of saidelectrodes.

13. A spark plug comprising a pair of relatively rotatable electrodes.one of said electrodeshaving a substantially cylindrical surface forsparking cooperation With the other electrodeJ and means mounting saidother electrode and providing a bearing therefor in the Hist-mentionedelectrode, said means having a part operalble for cleaning thecylindrical sparking surface.

14. A spark plug comprising a pai-r of relatively rotatable eleotrodes,one of said electrodes having a point for sparking cooperation with avcylindrical surface. formed in the other electrode, and means having apart mounting the first-mentioned electrode and providing a bearingtherefor in the last-mentioned electrode, said means centering saidelectrodes to provide a substantially uniform spark gap in all positionsof adjustment.

15. A spark plug comprising a pair of relatively rotatable electrodes,one of said electrodes having a point for sparking cooperation with acylindrical surface formed in the other electrode, and means mountingthe firstmentioned electrode, providing a bearing therefor in thelast-mentioned electrode, said means centering said electrodes toprovide a substantially uniform spark gap in all positions of adjnstment, said means having a part formed to clean the cylindricalsparking surface.

1G. A spark plug comprising a pairof electrodes ada ptcd for sparkingcooperation, one of said electrodes having a cylindrical sparkingsurface, and means rotatable in one of said electrodes formed forcontact with said cylindrical surface, said means having a part operablefrom the exterior. of the spark plug when applied in operative positionon an internal con'ibustion engine.

In testimonywhereof, I atiix my signature.

FREDERICK L. FOX.

